Heretofore, to administer a drug or the like to the biological surface of a patient, that is, the surface of the skin or mucous membrane, a method of applying a liquid substance or a powdery substance has been employed in most cases. However, since the area to which a drug can be applied is limited to the surface of the skin, a patient experiences a daily basis the fall-off of the applied drug by perspiration or contact with foreign matter, thereby making it difficult to administer a suitable amount of a drug effectively.
As an alternative to the application of a drug to the biological surface, there is proposed the administration of a drug into a living body by means of a microneedle. Also, proposals have been made to improve the puncture property of the microneedle.
For instance, in the methods of Patent Document 1 and Patent Document 2, there are proposed a microneedle and a microneedle array both of which are hardly broken and bent. However, the Puncture properties of the microneedle and the microneedle array are not satisfactory.
Patent Document 3 proposes a method of facilitating puncture by curving a conical surface or a pyramid surface toward the inside of a microneedle. However, since the method disclosed by Patent Document 3 makes use of volume shrinkage when a polymer solution is applied to a stamper to be gelled and dried, it is not suitable for a thermoplastic resin.
Patent Document 4 discloses a microneedle which is formed from a water-soluble or water-swellable resin, shaped like a spindle, a truncated pyramid or a conical pyramid and coated with a lubricant component.
Patent Document 5 discloses a method of administering a drug beneath the epidermis by loading a microneedle with a drug efficiently. This is a technology which can be applied to a liquid drug but not satisfactory as a technology which can achieve puncture property, the amount of the loaded drug and medication property for a solid drug.    (Patent Document 1) JP-A 2007-130030    (Patent Document 2) JP-A 2007-190112    (Patent Document 3) JP-A 2008-142183    (Patent Document 4) JP-A 2010-029634    (Patent Document 5) JP-A 2007-260351